The present invention generally relates to improved adjustable pedal assemblies for motor vehicles and, more particularly, to control systems for adjusting control pedals to desired positions.
Control pedals are typically provided in a motor vehicle, such as an automobile, which are foot operated by the driver. Separate control pedals are provided for operating brakes and an engine throttle. When the motor vehicle has a manual transmission, a third control pedal is provided for operating a transmission clutch. A front seat of the motor vehicle is typically mounted on tracks so that the seat is forwardly and rearwardly adjustable along the tracks to a plurality of positions so that the driver can adjust the front seat to the most advantageous position for working the control pedals.
This adjustment method of moving the front seat along the tracks generally fills the need to accommodate drivers of various size, but it raises several concerns. First, this adjustment method still may not accommodate all drivers due to very wide differences in anatomical dimensions of drivers. Second, the necessary position of the seat may be uncomfortable for some drivers. Therefore, it is desirable to have an additional or alternate adjustment method to accommodate drivers of various size.
Many proposals have been made to selectively adjust the position of the control pedals relative to the steering wheel and the front seat in addition to adjusting the front seat in order to accommodate drivers of various size. These adjustable control pedals can actuate either a cable which is connected to an engine throttle, for example, or an electronic throttle control (ETC) where an electric signal is sent to the engine throttle which is proportional to the positioning of the pedal. Such xe2x80x9cdrive-by-wirexe2x80x9d ETC pedals were adapted from fly-by-wirexe2x80x9d aircraft pedals, and the ETC can be, for example, either a dual slope potentiometer where the electric signal is proportional to rotation of the pedal, or a linear variable displacement transducer (LVDT) where the electric signal is proportional to linear displacement of the pedal or a carrier operatively connected to the pedal. See, for example, U.S. Pat. No. 5,056,742 to Sakurai showing adjustable pedals which control brakes and rudders of a motor vehicle such as an aircraft. A mounting frame or carrier is mounted in a base frame or support structure so that the carrier can be adjusted forward or rearward by operation of a screw device or drive assembly. Pedals are pivotally connected directly to the multi-part carrier for pivotal movement relative to the carrier and are moved to various adjusted positions with the forward/rearward movement of the carrier relative to the support structure. Transducers or generator means are mounted on the carrier and move with the carrier to the various adjusted positions. These transducers have outputs responsive to the pivotal movement of the pedals relative to the carrier which vary in magnitude in proportion to the extent of movement of the pedals relative to the carrier. It is readily apparent to those skilled in the art of adjustable control pedals that the pedals connected to the carrier can have many different forms depending on the requirements of the particular motor vehicle such as, for example, in automobiles the pedal is typically in the form of a pedal arm extending from a pivot connection to a lower end having a pad.
U.S. Pat. Nos. 5,632,183, 5,697,260, 5,722,302, 5,819,593, 5,937,707, and 5,964,125, the disclosures of which are expressly incorporated herein in their entirety by reference, each disclose an example of an adjustable control pedal assembly. This control pedal assembly includes a hollow guide tube, a rotatable screw shaft coaxially extending within the guide tube, a nut in threaded engagement with the screw shaft and slidable within the guide tube, and a control pedal rigidly connected to the nut. The control pedal is moved forward and rearward when an electric motor rotates the screw shaft to translate the nut along the screw shaft within the guide tube. While this control pedal assembly may adequately adjust the position of the control pedal to accommodate drivers of various size, this control pedal assembly is relatively complex and expensive to produce. The relatively high cost is particularly due to the quantity of high-precision machined parts such as, for example, the guide tube and due to the quantity of welded joints.
U.S. Pat. Nos. 3,643,525 and 3,643,524, the disclosures of which are expressly incorporated herein in their entirety by reference, each disclose an example of an adjustable control pedal assembly which is much less expensive to produce. This control pedal assembly includes an upper arm having a single horizontal slot, a rotatable screw shaft attached to the upper arm and extending along the slot, a nut in threaded engagement with the screw shaft and having a pin slidable within the slot, and a control pedal rigidly connected to the nut. The control pedal is moved forward and rearward when an electric motor rotates the screw shaft to translate the nut along the screw shaft. While this control pedal assembly may adequately adjust the position of the control pedal to accommodate drivers of various size and is relatively inexpensive to produce, this control pedal is relatively unstable and can have a relatively large amount of lash. That is, components of the control pedal are subject to vibration during regular operation of the motor vehicle causing the components to rub or strike together causing undesirable noise.
While these adjustable pedal systems may adequately adjust the position of control pedals, these systems often do not know the exact location of the control pedal and/or can cause injury or damage when the control pedals engage an obstruction. Accordingly, there is a need in the art for an adjustable pedal assembly which selectively adjusts the position of the control pedal to accommodate drivers of various size, is relatively simple and inexpensive to produce, is able reset in order to identify the exact position of the control pedal, is able to detect when an obstruction is engaged during movement of the control pedal, and/or is highly reliable to operate.
The present invention provides an adjustable control pedal for a motor vehicle which overcomes at least some of the above-noted problems of the related art. According to the present invention, an adjustable pedal assembly comprises, in combination, a carrier, a lower arm supported by the carrier and operatively connected to the carrier for selected movement relative to the carrier, and a drive assembly operatively connected to the lower arm to selectively move the lower arm relative to the carrier. The drive assembly comprises a drive screw connected to one of the lower arm and the carrier, a drive nut connected to the other of the lower arm and the carrier and cooperating with the drive screw such that the drive nut travels along the drive screw upon rotation of the drive screw, and an electric motor operatively connected to the drive screw to selectively rotate the drive screw. A sensor is provided which is adapted to detect motion information upon rotation of the drive screw. A controller receives the motion information and is adapted to activate the electric motor upon initialization of the controller to move the lower arm in a first direction until a first mechanical stop is engaged and establish a home stop position and to move the lower arm in the other direction opposite the first direction until a second mechanical stop is engaged and establish a travel stop position. The home stop position and the travel stop position represent the mechanical limits of travel for the lower arm.
According to another aspect of the present invention, an adjustable pedal assembly comprises, in combination, a carrier, a lower arm supported by the carrier and operatively connected to the carrier for selected movement relative to the carrier, and a drive assembly operatively connected to the lower arm to selectively move the lower arm relative to the carrier. The drive assembly comprises a drive screw connected to one of the lower arm and the carrier, a drive nut connected to the other of the lower arm and the carrier and cooperating with the drive screw such that the drive nut travels along the drive screw upon rotation of the drive screw, and an electric motor operatively connected to the drive screw to selectively rotate the drive screw. A sensor is provided which is adapted to detect motion information upon rotation of the drive screw. A controller is adapted to selectively activate the electric motor to move the lower arm, to receive the motion information, and to determine stall conditions of the lower arm based on the motion information during movement of the lower arm.
From the foregoing disclosure and the following more detailed description of various preferred embodiments it will be apparent to those skilled in the art that the present invention provides a significant advance in the technology and art of adjustable control pedal assemblies. Particularly significant in this regard is the potential the invention affords for providing a high quality, feature-rich, low cost assembly. Additional features and advantages of various preferred embodiments will be better understood in view of the detailed description provided below.